1. Field of the Invention
This invention relates to an apparatus and method for identifying individual conductors in a multi-conductor cable.
2. Description of the Related Art
It is important to be able to identify a particular conductor in a group of conductors in a wide variety of contexts. For example, in installing a computer network a multi-conductor cable having as many as fifty conductors might be strung among a number of different locations. In such a system, it is necessary to identify each individual conductor at each location so that the computer can be connected to the cable conductors in the proper manner. Other common examples exist such as: the wiring in a complex machine, such as a ship or an airplane, where a large number of conductors for a wide variety of purposes are strung together in a conductor bundle; the wiring in commercial buildings or factories where a large number of conductors might be disposed in a buss box with individual conductors branching from the buss box to remote locations; and a relatively short wiring harness having a large number of conductors.
While the need for identifying individual conductors in a group of conductors or cable is readily appreciated, known methods for such identification are deficient in many respects. Perhaps the most common method of identifying individual conductors is simply to place a worker at each end of the group of conductors or cable with some form of communication, such as a walkie-talkie or telephone. While earth ground or machine frame can sometimes be used as a reference conductor between the two ends of the cable, it is often necessary to provide a separate ground or reference strung between the two workers to provide a common reference. In the identification procedure, one worker initiates a signal on a particular conductor and the other worker hunts through the bundle of conductors to find the signal. If a short or open circuit condition is not encountered, the conductor with the signal is eventually found, the conductor tagged and segregated, and the process repeated until all of the conductors are identified. This process is tedious, and also tends to become very chaotic when a short circuit or open circuit condition is inadvertently encountered. This process also requires that a reliable reference conductor be somehow provided between the two workers.
Several attempts have been made at providing devices which can assist a worker in identifying a particular conductor. For example, U.S. Pat. No. 4,445,086 uses a transmitter and receiver unit grounded to the hull of a ship and connected to the ends of a conductor bundle. However, in this approach an identical signal is applied to each conductor and depends upon operator skill in recognizing illumination of a diode connected to each conductor. U.S. Pat. No. 3,742,350 is slightly more advantageous in that it identifies each individual conductor in a conductor bundle. However, this approach uses a unique binary code transmitted down each conductor. Applying a distinct binary code is a cumbersome process and this process also must rely upon an external conductor or ground.